The CEC value included on typical soil testing laboratory reports is calculated by adding together the
concentrations (expressed as milliequivalents of charge per 100 grams of soil) of potassium, magnesium,
calcium, sodium and hydrogen, which are extracted from soils using an appropriate extraction method. The
University of Georgia Soil Testing Laboratory uses the Mehlich I procedure, based on a double acid (0.05 N
HCl + 0.025 N H2
SO4
) extracting solution. This method is appropriate for acidic, low CEC soils, which are
commonly found in Georgia. The CEC of soils containing large amounts of clay or organic matter, or that are
alkaline, cannot be satisfactorily analyzed using the Mehlich I extract. Other soil extraction methodsshould
be used on these types of soils.